This invention relates to a filling aid for a medicant syringe to assist the user in the filling of the syringe and to prevent the loading of the syringe with too much medicant which would result in an overdose injection of the medicant; and more particularly to such device for use by persons who self-administer medicant by means of a syringe, as a safety device to prevent inadvertent excessive filling of the syringe.
This invention is concerned with the problem of assuring accurate dosage of medicant injected by syringe, where the medicant is self-administered or is administered by other members of the household. In many cases the amount of the dosage for each injection is quite critical and, while syringes are marked with gradations to indicate the amount of the dosage, it is relatively easy for users to misread the syringe and therefore inject either an inadequate dose or an excessive dose of medicant. The misreading of the syringe gradations could occur for any number of reasons including obscured indicia on the syringe, poor lighting, simple carelessness, inexperience, or impaired eyesight on the part of the user or the person administering the injection.
A principal object of this invention therefore is to provide a filling aid for medicant syringes, including either disposable or reuseable syringes, which filling aid can be pre-adjusted for use with a particular syringe to limit the amount of medicant which can be received in the syringe and therefore prevent an overdose.
Another object of this invention is to provide such a syringe filling aid which includes an automatic overfill and air ejection control.
A further object of this invention is to provide such a filling aid which can be manufactured at a reasonable cost, which is easy to use, and which is effective and reliable for the intended purpose.
These objects are accomplished in an accessory aid device for use with a medicant syringe which includes an elongated barrel, a needle projecting axially from one end of the barrel, and a plunger projecting from the other end of the barrel. The aid device comprises an elongated body including a hollow sleeve and an end piece secured to one end of the sleeve, the end piece having means for resiliently clamping the syringe barrel thereto, with the longitudinal axis of the syringe and aid device being aligned in parallel relation. The clamping means includes means for preventing relative axial movement of the syringe and aid device. A threaded shaft is disposed within the device being coupled to the end piece for rotation within the body. The body is provided with a longitudinal slot in one wall. A threaded lug is mounted on the shaft for movement therealong in response to rotation of the shaft, the lug having a tab projecting radially into the sleeve slot and disposed to be engaged by the plunger handle of a syringe clamped to the device. The dog is selectively positionable relative to the clamping end piece to limit the extent of withdrawal of the syringe plunger.
The novel features and the advantages of the invention, as well as additional objects thereof, will be understood more fully from the following description when read in connection with the accompanying drawings.